Why should metal tile roofs typically not omit underlayment?

Metal tile roofs should typically include an underlayment to protect against water infiltration. Underlayment serves as an additional barrier beneath the roofing material, which is crucial in preventing moisture from penetrating into the roofing system and, ultimately, the structure.

In the event of a storm or heavy rain, wind-driven rain can find its way under the metal tiles. Without an underlayment, this water could seep into the roof deck and cause significant damage, leading to mold growth, structural decay, and other costly repairs. The underlayment acts as a safeguard, catching any water that could potentially bypass the tiles and directing it away from sensitive areas, thereby enhancing the overall durability and longevity of the roofing system.

While other choices may touch upon relevant aspects of roofing materials, they do not directly address the primary reason for the necessity of underlayment in preventing water infiltration.